Unit and Currency Conversion Reference
Every common unit and currency conversion, each with a working calculator, the formula and a reference table.
Conversion reference
Direct answers for the conversions people look up most, each with a calculator, the formula and a full reference table.
Length
Weight
Volume
Area
Speed
Data
Time
Temperature
Currency
How these pages work
Every page here does the same three things. It answers the conversion immediately with a calculator that updates as you type, it shows the formula so you can check the arithmetic or reuse it in a spreadsheet, and it gives a reference table you can scan without typing anything at all. Nothing is sent to a server: the arithmetic runs in your browser, which is why the pages keep working with no connection once they have loaded.
Each page also carries a mental shortcut — the rough version you can do in your head when an estimate is enough — with an honest note about how far that shortcut drifts from the exact answer. Knowing that multiplying miles by 1.6 lands within a percent of correct is more useful day to day than knowing the factor to five decimal places.
About the currency rates
The currency pages use mid-market rates, refreshed daily. That is the midpoint of the wholesale market — the rate quoted in the news, and the number to compare a bank or transfer provider against rather than a rate you can transact at yourself. The gap between the mid-market rate and what you are actually offered is where providers make their money, and on most routes it is wider than the fee they advertise.
Need a conversion that is not here?
These pages cover what gets looked up most often. For anything else, the unit converter handles the full set of units, and the currency converter covers every pair rather than the common corridors listed above. Both are free, need no account, and work the same way.